Method for manufacturing optical articles

Abstract

To provide a new optical article manufacturing method with which it is possible to manufacture an optical article that has a cured layer formed by photopolymerization and that excels in transparency.SOLUTION: Provided is an optical article manufacturing method that includes applying a polymerizable composition to a substrate and forming a coating layer, and irradiating the coating layer with light from a light source that emits light of a wavelength band ranging from ultraviolet rays to visible rays and applying a curing process to the coating layer. The polymerizable composition includes one or more polymerizable compounds in molecular weight of 500 or less, a photopolymerization initiator having absorption in at least some of the wavelength regions of the visible rays, and an ultraviolet-absorbing compound. During light irradiation, an ultraviolet ray shielding filter is arranged between the light source and the coating layer and light irradiation is applied in at least some period from the initiation of light irradiation.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing optical articles. [Background technology]

[0002] Many optical articles have one or more coating layers on a substrate, and these coating layers impart various properties to the optical articles. In recent years, it has become common practice to form such coating layers as cured layers cured by photopolymerization (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-181455 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Forming a coating layer (cured layer) by photopolymerization has advantages over other coating layer formation methods such as thermosetting, penetration / evaporation drying, and oxidative polymerization, including reduced environmental impact due to reduced use of volatile organic compounds and improved productivity due to shorter curing time. However, the inventors' research has revealed that in optical articles where a cured layer is formed by photopolymerization, defects may occur on the surface of the cured layer, which can reduce the transparency of the optical article.

[0005] In view of the foregoing, one aspect of the present invention aims to provide a novel method for manufacturing optical articles, which enables the manufacture of optical articles having a cured layer formed by photopolymerization and exhibiting excellent transparency. [Means for solving the problem]

[0006] One aspect of the present invention is, Applying a polymerizable composition onto a substrate to form a coating layer, The coating layer is cured by irradiating it with light from a light source that emits light in the wavelength range from ultraviolet to visible light. Includes, The above polymerizable composition is One or more polymerizable compounds with a molecular weight of 500 or less, A photopolymerization initiator having absorption in at least a portion of the wavelength range of visible light, UV-absorbing compounds, Includes, A method for manufacturing an optical article, wherein, during the above-mentioned light irradiation, an ultraviolet-blocking filter is placed between the light source and the coated layer for at least a portion of the period from the start of the light irradiation. Regarding.

[0007] Through repeated investigations, the inventors have newly discovered that the surface defects of the cured layer described above tend to occur more easily in cured layers formed by photopolymerization of a polymerizable composition containing an ultraviolet-absorbing compound and a polymerizable compound with a molecular weight of 500 or less. In this regard, the inventors have the following inference. By applying a polymerizable composition onto a substrate and irradiating the resulting coating layer with light, the coating layer can be cured by photopolymerization to form a cured layer. On the other hand, it is presumed that when ultraviolet-absorbing compounds absorb ultraviolet light, molecular motion occurs, which makes them more prone to aggregation. When an ultraviolet-absorbing compound is included in a polymerizable composition, the aggregation of molecules as described above occurs in the initial stages of polymerization, inhibiting the polymerization of the polymerizable compound. In particular, polymerizable compounds with a molecular weight of 500 or less are thought to be more susceptible to this polymerization inhibition. The inventors surmise that this may be a factor in the occurrence of defects on the surface of the cured layer. In contrast, the above manufacturing method uses a light source that emits light in the wavelength range from ultraviolet to visible light and a photopolymerization initiator that absorbs at least a portion of the visible light wavelength range. Furthermore, for at least a portion of the time from the start of light irradiation for photopolymerization, i.e., at least in the initial stages of polymerization, the irradiation of ultraviolet light to the coated layer of the polymerizable composition is blocked by an ultraviolet blocking filter. This prevents ultraviolet absorption by the ultraviolet-absorbing compound in the initial stages of polymerization. However, the coated layer contains a photopolymerization initiator that can function when irradiated with light on the wavelength side longer than the ultraviolet wavelength range, which is contained in the light emitted from the light source. Therefore, this photopolymerization initiator allows the polymerization reaction of the polymerizable compound to proceed even when ultraviolet irradiation is blocked. Thus, in the initial stages of polymerization when ultraviolet light is blocked by the filter, the influence of aggregation between molecules of the ultraviolet-absorbing compound can be eliminated or reduced, and the polymerization of low molecular weight polymerizable compounds with a molecular weight of 500 or less can proceed smoothly. The inventors surmise that this suppresses the occurrence of defects on the surface of the cured layer, which is why it is possible to manufacture optical articles with excellent transparency using the above manufacturing method. However, the present invention is not limited to the surmise described herein. [Effects of the Invention]

[0008] According to one aspect of the present invention, it is possible to provide a method for manufacturing optical articles that have a cured layer formed by photopolymerization and exhibit excellent transparency. [Brief explanation of the drawing]

[0009] [Figure 1] The transmission spectrum of filter A used in the example and the transmission spectrum of filter B used in the comparative example are shown. [Figure 2] The absorption spectrum of the photoradical polymerization initiator Omnirad819 from IGM Resin BV is shown. [Figure 3]The film thickness measurement results of the photochromic layer by a reflection-type non-contact film thickness measuring device for the spectacle lenses produced in Example 1 and the spectacle lenses produced in Comparative Example 2 are shown.

Mode for Carrying Out the Invention

[0010] In the present invention and this specification, "ultraviolet rays" refer to electromagnetic waves in the wavelength range of 300 nm or more and 400 nm or less, and "visible light" refers to electromagnetic waves in the wavelength range of more than 400 nm and 780 nm or less.

[0011] In the present invention and this specification, "ultraviolet absorbing compound" refers to a compound having absorption at a wavelength of at least 400 nm.

[0012] In the present invention and this specification, "ultraviolet blocking filter" refers to a filter having a light transmittance of less than 5% in the ultraviolet wavelength range (300 nm or more and 400 nm or less) of this filter. That is, the maximum transmittance of the above filter in the ultraviolet wavelength range (300 nm or more and 400 nm or less) is less than 5%.

[0013] In the present invention and this specification, "photoinitiator having absorption in at least a part of the visible light wavelength range" refers to a compound that can function as a photoinitiator and has absorption in at least a part of the visible light wavelength range, that is, the wavelength range of more than 400 nm and 780 nm or less.

[0014] In the present invention and this specification, "having absorption" means that the molar absorption coefficient is more than 0 L·mol -1 ,

[0015] , -1 , , , , ,

[0014] , ·cm -1 above. The molar absorption coefficient is a coefficient obtained by converting the absorbance of a sample when using a cell with a sample concentration of 1 mol / L and an optical path length of 1 cm, and can be determined by a known method.

[0015] In the present invention and this specification, "light source that emits light in a wavelength range from ultraviolet to visible light" means a light source whose emission wavelength range includes at least a part of the ultraviolet wavelength range and at least a part of the visible light wavelength range.

[0016] The above manufacturing method will be explained in more detail below.

[0017] <Base material> In the above manufacturing method, a polymerizable composition is applied to a substrate to form a coating layer. The substrate can be selected according to the type of optical article. Optical articles include various items such as eyeglass lenses, goggle lenses, visor portions of sun visors, and helmet shield components. As an example of a substrate, an eyeglass lens substrate can be a plastic lens substrate or a glass lens substrate. A glass lens substrate can be, for example, a lens substrate made of inorganic glass. As a lens substrate, a plastic lens substrate is preferred from the viewpoint of being lightweight, less prone to breakage, and easy to handle. Examples of plastic lens substrates include styrene resins such as (meth)acrylic resin, polycarbonate resin, allyl resin, allyl carbonate resin such as diethylene glycol bisallyl carbonate resin (CR-39), vinyl resin, polyester resin, polyether resin, urethane resin obtained by the reaction of an isocyanate compound with a hydroxyl compound such as diethylene glycol, thiourethane resin obtained by the reaction of an isocyanate compound with a polythiol compound, and cured products (generally called transparent resins) obtained by curing a curable composition containing a (thio)epoxy compound having one or more disulfide bonds in the molecule. The lens substrate may be undyed (colorless lens) or dyed (dyed lens). The refractive index of the lens substrate can be, for example, about 1.50 to 1.75. However, the refractive index of the lens substrate is not limited to the above range, and may be within the above range or outside of it. In the present invention and this specification, refractive index refers to the refractive index for light with a wavelength of 500 nm. Furthermore, the lens base material may be a lens with refractive power (a so-called prescription lens) or a lens without refractive power (a so-called non-prescription lens).

[0018] Eyeglass lenses can be various types of lenses, such as single-vision lenses, multi-vision lenses, and progressive lenses. The type of lens is determined by the surface shape of both sides of the lens substrate. The surface of the lens substrate may be convex, concave, or flat. In typical lens substrates and eyeglass lenses, the surface facing the object is convex, and the surface facing the eyeball is concave. However, the present invention is not limited thereto. When manufacturing eyeglass lenses by the above manufacturing method, the polymerizable composition coating layer can be formed on the surface facing the object and / or the surface facing the eyeball of the lens substrate.

[0019] The polymerizable composition coating layer may be applied directly to the surface of the substrate, or indirectly via one or more other layers formed on the substrate. Examples of other layers include a hard coat layer, a primer layer to improve the adhesion between the cured layer formed by curing the polymerizable composition and the substrate, and so on. Furthermore, a substrate with a hard coat layer can also be used as the substrate.

[0020] [Formation of a coating layer of polymerizable composition] <Application Method> Known coating methods such as spin coating and dip coating can be used to apply the polymerizable composition. From the viewpoint of uniformity of coating, spin coating is preferred.

[0021] <Polymerizable composition> (polymerizable compound) In the present invention and this specification, "polymerizable composition" means a composition containing one or more polymerizable compounds. "Polymerizable compound" means a compound having one or more polymerizable groups in one molecule. In the above production method, a polymerizable composition containing at least one polymerizable compound with a molecular weight of 500 or less is used as the polymerizable compound. In the present invention and this specification, the molecular weight of the polymer is determined by the structural formula determined by structural analysis of the compound or by the theoretical molecular weight calculated from the raw material charge ratio during production. A specific example of a polymerizable compound with a molecular weight of 500 or less is (meth)acrylate. In the present invention and this specification, "(meth)acrylate" is used to encompass both acrylate and methacrylate. "Acrylate" is a compound having one or more acryloyl groups in one molecule. "Methacrylate" is a compound having one or more methacryloyl groups in one molecule. For (meth)acrylate, the functional number is the number of groups selected from the group consisting of acryloyl groups and methacryloyl groups contained in one molecule. In the present invention and this specification, "methacrylate" refers to a material containing only a methacryloyl group as the (meth)acryloyl group, while a material containing both an acryloyl group and a methacryloyl group as the (meth)acryloyl group is called an acrylate. The acryloyl group may be included in the form of an acryloyloxy group, and the methacryloyl group may be included in the form of a methacryloyloxy group. In the following, "(meth)acryloyl group" is used to encompass both an acryloyl group and a methacryloyl group, and "(meth)acryloyloxy group" is used to encompass both an acryloyloxy group and a methacryloyloxy group. Furthermore, unless otherwise specified, the groups described may have substituents or may be unsubstituted. When a group has substituents, examples of substituents include alkyl groups (e.g., alkyl groups with 1 to 6 carbon atoms), hydroxyl groups, alkoxy groups (e.g., alkoxy groups with 1 to 6 carbon atoms), halogen atoms (e.g., fluorine atoms, chlorine atoms, bromine atoms), cyano groups, amino groups, nitro groups, acyl groups, carboxyl groups, etc. Furthermore, for groups with substituents, "number of carbon atoms" refers to the number of carbon atoms in the portion that does not contain the substituent.

[0022] Specific examples of polymerizable compounds with a molecular weight of 500 or less include the following components B and C. Furthermore, in one embodiment, the polymerizable composition used to form the coating layer in the above manufacturing method may contain only one or more polymerizable compounds with a molecular weight of 500 or less as polymerizable compounds. In another embodiment, the polymerizable composition used to form the coating layer in the above manufacturing method may contain one or more polymerizable compounds with a molecular weight of 500 or less and one or more polymerizable compounds with a molecular weight greater than 500 as polymerizable compounds. Specific examples of polymerizable compounds with a molecular weight greater than 500 include the following component A. Hereinafter, polymerizable compounds with a molecular weight of 500 or less will be referred to as "low molecular weight polymerizable compounds," and polymerizable compounds with a molecular weight greater than 500 will be referred to as "high molecular weight polymerizable compounds." When the polymerizable composition used to form the coating layer in the above manufacturing method contains only low molecular weight polymerizable compounds as polymerizable compounds, the content of low molecular weight polymerizable compounds (the sum of two or more low molecular weight polymerizable compounds if they are included) is 100% by mass, with the total amount of polymerizable compounds being 100% by mass. On the other hand, if the polymerizable composition used to form the coating layer in the above manufacturing method contains both a low molecular weight polymerizable compound and a high molecular weight polymerizable compound as polymerizable compounds, the content of the high molecular weight polymerizable compound (the sum of two or more high molecular weight polymerizable compounds if included) may be 50% by mass or less, greater than 50% by mass, or 60% by mass or more, with the total amount of polymerizable compounds being 100% by mass. Furthermore, the content of the high molecular weight polymerizable compound can be, for example, 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less. If the polymerizable composition used to form the coating layer in the above manufacturing method contains both a low molecular weight polymerizable compound and a high molecular weight polymerizable compound, the content of the low molecular weight polymerizable compound (the sum of two or more low molecular weight polymerizable compounds if included) may be greater than 50% by mass, 50% by mass or less, 40% by mass or less, or 5% by mass or more, 10% by mass or more, or 15% by mass or more, with the total amount of polymerizable compounds being 100% by mass.

[0023] Ingredient A Component A is an acyclic (meth)acrylate with a molecular weight greater than 500. In this invention and specification, "acyclic" means not containing a cyclic structure. In contrast, "cyclic" means containing a cyclic structure. An acyclic (meth)acrylate refers to a monofunctional or more (meth)acrylate that does not contain a cyclic structure.

[0024] Component A can be a monofunctional or bifunctional or more functional (meth)acrylate, preferably a bifunctional or trifunctional (meth)acrylate, and more preferably a bifunctional (meth)acrylate. A specific example of component A is polyalkylene glycol di(meth)acrylate. For example, polyalkylene glycol di(meth)acrylate is given by the following formula 2: [ka] This can be shown by the following equation. In equation 2, R 3 and R 4 Each of the following independently represents a hydrogen atom or a methyl group, R represents an alkylene group, and n indicates the number of repeating alkoxy groups represented by RO, which is 2 or more. Examples of alkylene groups represented by R include ethylene, propylene, and tetramethylene groups. n is 2 or more and can be, for example, 30 or less, 25 or less, or 20 or less. Specific examples of polyalkylene glycol di(meth)acrylate include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate. Component A may contain only an acryloyl group, only a methacryloyl group, or both an acryloyl and a methacryloyl group as the (meth)acryloyl group.

[0025] The molecular weight of component A can be greater than 500, 510 or more, 520 or more, 550 or more, 570 or more, 600 or more, 630 or more, or 650 or more. From the viewpoint of increasing the hardness of the hardened layer, the molecular weight of component A can be, for example, 2000 or less, 1500 or less, 1200 or less, 1000 or less, or 800 or less.

[0026] Component B Component B has a molecular weight of 500 or less and is defined by the following formula 1: [ka] It is a (meth)acrylate represented by .

[0027] In formula 1, R 1 and R 2 Each of these independently represents a hydrogen atom or a methyl group, and m represents an integer greater than or equal to 1. m can be 1 or greater, for example, 10 or less, 9 or less, 8 or less, 7 or less, or 6 or less.

[0028] The molecular weight of component B is 500 or less, and can be 450 or less, 400 or less, 350 or less, or 300 or less. Furthermore, the molecular weight of component B can be, for example, 100 or more, 150 or more, or 200 or more.

[0029] Component B may contain only an acryloyl group, only a methacryloyl group, or both an acryloyl and a methacryloyl group as the (meth)acryloyl group. Specific examples of component B include 1,9-nonanediol di(meth)acrylate (also called "nonamethylene glycol di(meth)acrylate"), 1,6-hexanediol di(meth)acrylate, and 1,10-decanediol di(meth)acrylate.

[0030] Component C Component C is a trifunctional (meth)acrylate with a molecular weight of 500 or less, preferably a trifunctional or tetrafunctional (meth)acrylate, and more preferably a trifunctional (meth)acrylate. Specific examples of component C include, for example, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, and tetramethylolmethane tri(meth)acrylate. The molecular weight of component C is 500 or less, and can be, for example, in the range of 200 to 400, but is not limited to this range. Component C may contain only an acryloyl group, only a methacryloyl group, or both an acryloyl group and a methacryloyl group as the (meth)acryloyl group.

[0031] The content of the polymerizable compound in the above polymerizable composition may be, for example, 80% by mass or more, 85% by mass or more, or 90% by mass or more, based on 100% by mass of the total amount of the composition. Alternatively, the content of the polymerizable compound in the above polymerizable composition may be, for example, 99% by mass or less, 95% by mass or less, 90% by mass or less, or 85% by mass or less, based on 100% by mass of the total amount of the composition. In the present invention and this specification, with respect to content, "total amount of composition" means the total amount of all components excluding the solvent in the case of a composition containing a solvent. The above composition may or may not contain a solvent. If a solvent is included, any solvent can be used in any amount, as long as it does not inhibit the progress of the polymerization reaction of the polymerizable composition.

[0032] <Photopolymerization initiator> In the above manufacturing method, the polymerizable composition used for forming the coating layer contains a photopolymerization initiator having absorption in at least a part of the wavelength range of visible light (i.e., the wavelength range exceeding 400 nm and not exceeding 780 nm) as a polymerization initiator. As such a photopolymerization initiator, from the viewpoint of allowing the polymerization reaction to proceed more favorably in the initial stage of polymerization where an ultraviolet blocking filter is used, it is preferable that the molar absorption coefficient at a wavelength of 420 nm is 160 L·mol -1 ·cm -1 or more. Further, the above molar absorption coefficient can be, for example, 5300 L·mol -1 ·cm -1 or less. Further, as the above photopolymerization initiator, it is preferable to use a compound having absorption in at least a part of the wavelength range of ultraviolet rays from the viewpoint of allowing the polymerization reaction to proceed more favorably after removing the ultraviolet blocking filter. As the photopolymerization initiator, a photo radical polymerization initiator is preferable. Examples of the photo radical polymerization initiator include α-hydroxy ketone, α-amino ketone, oxime ester, phosphine oxide, 2,4,5-triaryl imidazole dimer, benzophenone compound, quinone compound, benzoin ether, benzoin compound, benzyl compound, acridine compound and the like. The content of the photopolymerization initiator can be, for example, in the range of from 0.1 to 5% by mass based on 100% by mass of the total amount of the composition.

[0033] <Ultraviolet Absorbing Compound> The polymerizable composition used to form the coating layer in the above manufacturing method includes an ultraviolet-absorbing compound. For example, a photochromic compound can be cited as an ultraviolet-absorbing compound. A photochromic compound is a compound that has the property of coloring under irradiation with light in a photoresponsive wavelength range and fading under non-irradiation conditions (photochromic performance). As an example, a photochromic compound undergoes a structural transformation into a colored form after being irradiated with light such as sunlight, going through an excited state. The structure after the structural transformation via light irradiation can be called the "colored form." In contrast, the structure before light irradiation can be called the "colorless form." Note that "colorless" in the case of a colorless form is not limited to being completely colorless, but includes cases where the color is lighter than that of the colored form. For photochromic compounds, the absorption characteristics refer to the absorption characteristics of the colorless form. That is, a photochromic compound being an ultraviolet-absorbing compound means that the structure of the colorless form has absorption at a wavelength of at least 400 nm. Examples of photochromic compounds include compounds with known skeletons exhibiting photochromic properties, such as flugimid compounds, spirooxazine compounds, chromene compounds, and indeno-condensed naphthopyran compounds. Photochromic compounds can be used individually or in combination of two or more.

[0034] In the above manufacturing method, the content of the ultraviolet-absorbing compound in the polymerizable composition used to form the coating layer can be, for example, about 0.1 to 15% by mass, based on 100% by mass of the total amount of the composition, but is not limited to this range.

[0035] The polymerizable composition may further contain, in any amount, known additives that are commonly added to polymerizable compositions, such as surfactants, antioxidants, radical scavengers, light stabilizers, color inhibitors, antistatic agents, fluorescent dyes, dyes, pigments, fragrances, plasticizers, and silane coupling agents. Known compounds can be used as these additives.

[0036] The polymerizable composition described above can be prepared by mixing the various components described above simultaneously or sequentially in any order.

[0037] [Curing treatment by light irradiation] In the above manufacturing method, the coated layer of the polymerizable composition is irradiated with light from a light source that emits light in the wavelength range from ultraviolet to visible light, and during the light irradiation, an ultraviolet blocking filter is placed between the light source and the coated layer for at least a portion of the time from the start of the light irradiation. As a result, ultraviolet irradiation to the coated layer can be blocked in the initial stages of polymerization, thereby eliminating or reducing the effects of aggregation between molecules of ultraviolet-absorbing compounds, and allowing the polymerization reaction of the low molecular weight polymerizable compound to proceed smoothly.

[0038] <Light source> The above manufacturing method uses a light source that emits light in a wavelength range from ultraviolet to visible light. As previously described, such a light source has an emission wavelength range that includes at least a portion of the ultraviolet wavelength range and at least a portion of the visible light wavelength range. For example, it can be a light source that has an emission wavelength range that includes at least a portion of the wavelength range between 300 nm and 600 nm (however, including at least a portion of the ultraviolet wavelength range and at least a portion of the visible light wavelength range). An example of such a light source is a metal halide lamp.

[0039] <UV blocking filter> As mentioned earlier, an ultraviolet blocking filter is a filter whose transmittance of light in the ultraviolet wavelength range (300 nm to 400 nm) is less than 5%. The inventors believe that blocking light in the ultraviolet wavelength range from the light source irradiated onto the coated layer during the initial polymerization stage with the above filter contributes to suppressing the occurrence of defects on the surface of the cured layer formed by curing the coated layer by photopolymerization. Details of this point have been described in detail earlier. As the ultraviolet irradiation filter, any commercially available filter with the above ultraviolet blocking properties can be used, or a filter manufactured by a known method can be used. Furthermore, the ultraviolet blocking properties of the ultraviolet blocking filter may be due to reflection, absorption, or both. In the initial stages of polymerization, to allow at least a portion of the visible light wavelength range from the light source to pass through the UV-blocking filter and irradiate the coated layer, the UV-blocking filter preferably has a transmittance of 5% or more for at least a portion of the visible light wavelength range (i.e., the wavelength range from 400 nm to 780 nm), with 10% or more, 20% or more, 30% or more, and 40% or more being more preferable in that order. Such transmittances can be, for example, 100% or less, less than 100%, and 90% or less.

[0040] <Hardening treatment> When irradiating the coated layer with light from the above-mentioned light source, an ultraviolet-blocking filter is placed between the light source and the coated layer for at least a portion of the time from the start of light irradiation to block ultraviolet radiation from reaching the coated layer. It is also possible to irradiate the coated layer with light from the light source with an ultraviolet-blocking filter placed between the light source and the coated layer for the entire duration of light irradiation. From the viewpoint of promoting a better polymerization reaction of polymerizable compounds, it is preferable to irradiate the coated layer with light from the light source with an ultraviolet-blocking filter placed between the light source and the coated layer for a portion of the time from the start of light irradiation, and then remove the ultraviolet-blocking filter from between the light source and the coated layer, and irradiate the layer without the ultraviolet-blocking filter interposed between the light source and the coated layer. In this case, the time during which the coated layer is irradiated with light from the light source through the ultraviolet-blocking filter can be, for example, more than 0 seconds and 5 seconds or less, with the start of light irradiation being 0 seconds, but is not limited to this. The time during which light irradiation is performed after the ultraviolet-blocking filter is removed from between the light source and the coated layer is not particularly limited.

[0041] Light irradiation can be carried out by placing the object to be irradiated (i.e., a laminate including at least a substrate and a coating layer of the polymerizable composition) inside a light irradiation device. Examples of the atmosphere inside the light irradiation device include a nitrogen atmosphere and an atmospheric atmosphere. The above-mentioned nitrogen atmosphere and the nitrogen atmosphere described later may be, for example, a nitrogen atmosphere with an oxygen concentration of 500 ppm or less (ppm is on a volume basis). The atmosphere inside the device can be made a nitrogen atmosphere by purging with nitrogen. The placement and removal of the ultraviolet blocking filter between the light source and the coating layer may be performed automatically by means of moving the ultraviolet blocking filter in the light irradiation device, or it may be performed manually.

[0042] The thickness of the hardened layer formed by the above hardening treatment can be determined according to the type of hardened layer. For example, if the hardened layer is a layer containing a photochromic compound as an ultraviolet-absorbing compound, i.e., a photochromic layer, the thickness of the photochromic layer is preferably in the range of 5 to 80 μm, and more preferably in the range of 20 to 60 μm.

[0043] [Possible layers to be added at will] In the above method for manufacturing optical articles, one or more layers may be further formed on the hardened layer described above. Examples of such layers include known functional layers for optical articles, such as hard coat layers, protective layers, anti-reflective layers, water-repellent or hydrophilic anti-fouling layers, anti-fogging layers, and primer layers for improving interlayer adhesion.

[0044] One form of the optical article described above is an eyeglass lens. Other forms of the optical article include lenses for goggles, visors for sun visors, and shield components for helmets. When the hardened layer of the optical article contains a photochromic compound as an ultraviolet-absorbing compound, it can be suitably used as an optical article having an anti-glare function.

[0045] By combining the above-mentioned spectacle lenses with a frame, eyeglasses can be manufactured. Such eyeglasses, for example, include spectacle lenses having a hardened layer (i.e., a photochromic layer) containing a photochromic compound. For example, outdoors, the photochromic compound contained in the photochromic layer can be colored by sunlight, exhibiting an anti-glare effect like sunglasses, and when returning indoors, the photochromic compound can fade, restoring transparency. Regarding the structure of the eyeglasses, such as the frame, known technologies can be applied. [Examples]

[0046] The present invention will be further described below with reference to examples. However, the present invention is not limited to the embodiments shown in the examples. Unless otherwise specified, the processes and evaluations described below were carried out in air at room temperature (20°C ± 5°C).

[0047] [Preparation of polymerizable compositions] <Polymerizable composition A> In a plastic container, component A is polyethylene glycol dimethacrylate (in formula 2 shown earlier, n=14, R is an ethylene group, R 3 and R 4A mixture of polymerizable compounds was obtained by mixing 68 parts by mass of methyl group (molecular weight 771), 20 parts by mass of component B, nonamethylene glycol dimethacrylate (molecular weight 296), and 12 parts by mass of component C, trimethylolpropane trimethacrylate (molecular weight 332). To the above mixture, 0.8 parts by mass of a photoradical polymerization initiator (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad819, manufactured by IGM Resin BV)), 1.0 part by mass of an antioxidant (ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate)), 1.0 part by mass of a photostabilizer (a mixture of bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and methyl(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate), and 3.7 parts by mass of a photochromic compound, which is an ultraviolet-absorbing compound (an indeno-condensed naphthopyran compound represented by the structural formula described in U.S. Patent No. 5645767), were mixed and thoroughly stirred. Subsequently, the mixture was degassed using a rotation-and-revolution type stirring and degassing apparatus. Based on the above, polymerizable composition A was prepared.

[0048] <Polymerizable composition B> Polymerizable composition B was prepared in the same manner as polymerizable composition A, except that the total amount of polymerizable compound was 100 parts by mass of nonamethylene glycol dimethacrylate (molecular weight 296), which is component B.

[0049] <Polymerizable composition C> The total amount of polymerizable compound is polyethylene glycol dimethacrylate, which is component A (in formula 2 shown above, n=14, R is an ethylene group, R 3 and R 4 Polymerizable composition C was prepared in the same manner as polymerizable composition A, except that 100 parts by mass of a methyl group (molecular weight 771) was used. Polymerizable composition C is a polymerizable composition that does not contain polymerizable compounds with a molecular weight of 500 or less.

[0050] [filter] The filters A and B described below are both commercially available products (Filter A: HOYA Corporation Sharp Cut Filter L39 (thickness 2.5 mm), Filter B: HOYA Corporation Sharp Cut Filter L42 (thickness 2.5 mm)). Figure 1 shows the transmission spectra of Filter A and Filter B. The transmission spectra shown in Figure 1 were obtained by measuring in the wavelength range of 300 to 800 nm using an ultraviolet-visible-near-infrared spectrophotometer (Hitachi High-Tech Science Co., Ltd. UH4150) with a slit width of 5 nm and a scan speed of 300 nm / min. Filter A is an ultraviolet-blocking filter, while Filter B is not an ultraviolet-blocking filter.

[0051] [Photopolymerization initiator] Figure 2 shows the absorption spectrum of the photoradical polymerization initiator Omnirad819 from IGM Resin BV. The molar extinction coefficient at a wavelength of 420 nm is 169 L·mol. -1 ·cm -1 That is the case. The absorption spectrum shown in Figure 2 was created as follows. Polymerizable composition A, which does not contain photochromic compounds, was placed in a synthetic quartz cell (optical path length 0.05 mm) as a measurement sample and its absorbance was measured. The measurement was performed using a UV-Vis-Near-Infrared spectrophotometer (Hitachi High-Tech Science Co., Ltd. UH4150) with a slit width of 5 nm and a scan speed of 300 nm / min in the wavelength range of 300 to 800 nm. The same measurement was performed on a reference sample with the same composition as the measurement sample except that it did not contain a polymerization initiator. The absorbance of the polymerization initiator was defined as the absorbance obtained by subtracting the absorbance obtained for the reference sample from the absorbance obtained for the measurement sample. From the measured absorbances, the molar extinction coefficient at each wavelength was determined using the Lambert-Beer law, and the absorption spectrum shown in Figure 2 was created.

[0052] [Fabrication of eyeglass lenses (photochromic lenses)] <Example 1> A polymerizable composition A was applied to the convex surface (object-side surface) of a plastic lens substrate (HOYA Corporation product name PHOENIX; center thickness 2.0 mm, radius 70 mm, S0.00) by spin coating to form a coating layer. A metal halide lamp was used as the light source. The metal halide lamp has an emission wavelength band in at least a portion of the wavelength range between 300 nm and 600 nm (however, this includes at least a portion of the ultraviolet wavelength range and at least a portion of the visible light wavelength range). The laminate of the substrate and the coating layer, which is the object to be irradiated, was placed inside the light irradiation device with the coating layer facing upwards. Light irradiation was performed with filter A placed between the light source and the coating layer for the first 1 second from the start of irradiation (0 seconds). After that, filter A was removed from between the light source and the coating layer, and light was continuously irradiated from the light source. Based on the above, we fabricated eyeglass lenses (photochromic lenses) having a photochromic layer as a cured layer on a substrate.

[0053] <Comparative Example 1> Except for using filter B instead of filter A, the eyeglass lenses were fabricated as described in Example 1.

[0054] <Comparative Example 2> Except for the fact that light irradiation was performed from the start of light irradiation to 1 second without placing filter A between the light source and the coated layer, the spectacle lens was manufactured in the same manner as described in Example 1.

[0055] <Comparative Example 3> Except for using polymerizable composition B instead of polymerizable composition A as the polymerizable composition, eyeglass lenses were manufactured in the same manner as described for Comparative Example 2.

[0056] <Example 2> Except for using polymerizable composition B instead of polymerizable composition A as the polymerizable composition, eyeglass lenses were manufactured as described in Example 1.

[0057] <Reference example 1> Except for using polymerizable composition C instead of polymerizable composition A as the polymerizable composition, eyeglass lenses were manufactured in the same manner as described for Comparative Example 2.

[0058] [Exterior evaluation] The appearance of the eyeglass lenses fabricated in the above examples, comparative examples, and reference examples was evaluated by visual inspection with the naked eye under indoor fluorescent lighting and by projection inspection using a projection inspection machine (Optical Modulex BA-H25, manufactured by Ushio Inc.). The projection inspection was performed with the eyeglass lenses placed between the light source and the screen of the projection inspection machine, emitting light of 800-1,200 Lux from the light source. The evaluation criteria were as follows. Good: No turbidity or shadows were observed during evaluation under indoor fluorescent lighting. No turbidity or shadows were observed during projection testing either. No Good: Cloudiness and / or shadows are observed in at least one of the evaluations under indoor fluorescent lighting and / or projection testing.

[0059] The results are shown in Table 1.

[0060] [Table 1]

[0061] The performance of the spectacle lenses fabricated in Example 1 and Comparative Example 2 as photochromic lenses was evaluated by the following methods.

[0062] (1) Visible light transmittance under non-irradiated conditions The transmittance (measurement wavelength: 550 nm) of each spectacle lens was measured using a spectrophotometer manufactured by Otsuka Electronics Industry Co., Ltd. before the following color density measurements were performed. A higher transmittance value (hereinafter referred to as "initial transmittance") indicates better visible light transmittance under non-irradiated conditions.

[0063] (2) Color density The color intensity was evaluated using the following method in accordance with JIS T7333:2005. The photochromic layer (cured layer obtained by curing the above polymerizable composition) of each spectacle lens was irradiated with light from a xenon lamp through an aeromass filter for 15 minutes (900 seconds) to cause the photochromic compound in the photochromic layer to develop color. The transmittance at the time of color development (measurement wavelength: 550 nm) was measured using a spectrophotometer manufactured by Otsuka Electronics Industry Co., Ltd. The above light irradiation was carried out so that the irradiance and tolerance of irradiance were the values ​​shown in Table 2 below, as specified in JIS T7333:2018.

[0064] [Table 2]

[0065] A smaller value for the transmittance measured above (hereinafter referred to as "transmittance at color development") indicates that the photochromic compound is developing color at a higher concentration.

[0066] (3) Fading rate (half-life) The fading rate of each spectacle lens was evaluated using the method described below. After measuring the transmittance at the time of color development as described in (2) above, the time required for the transmittance (measurement wavelength: 550nm) to become [(initial transmittance - transmittance at color development) / 2] (half-life) was measured from the time the light irradiation was stopped. The smaller the half-life value measured in this way, the faster the fading rate can be said to be.

[0067] The results are shown in Table 3.

[0068] [Table 3]

[0069] The results shown in Table 3 confirm that the spectacle lens produced in Example 1 exhibited a color density equivalent to that of the spectacle lens produced in Comparative Example 2, and also showed superior visible light transmittance under non-irradiated conditions and a faster fading rate compared to the spectacle lens produced in Comparative Example 2. The inventors believe that these results are due to the formation of a cured layer (photochromic layer) by the method described above, which suppressed aggregation of photochromic compound molecules while allowing the polymerization reaction of the low molecular weight polymerizable compound to proceed smoothly.

[0070] The thickness of the photochromic layer was measured for the spectacle lenses fabricated in Example 1 and Comparative Example 2 using a reflective, non-contact film thickness measuring device. The film thickness measurement results are shown in Figure 3. For reference, the measurement results for only the substrate without the photochromic layer are also shown in Figure 3. As shown in Figure 3, a signal was detected in the spectacle lens fabricated in Example 1, making it possible to measure the thickness of the photochromic layer. In contrast, as shown in Figure 3, no signal was detected in the spectacle lens fabricated in Comparative Example 2. Therefore, it is difficult to measure the thickness of the photochromic layer in the spectacle lens of Comparative Example 2 using a reflective, non-contact thickness measuring device. The above results are thought to be due to the higher surface smoothness of the photochromic layer in the spectacle lens fabricated in Example 1 compared to the spectacle lens fabricated in Comparative Example 2.

[0071] Finally, we will summarize each of the aforementioned aspects.

[0072] [1] Applying a polymerizable composition onto a substrate to form a coating layer, The coating layer is cured by irradiating it with light from a light source that emits light in the wavelength range from ultraviolet to visible light. Includes, The above polymerizable composition is One or more polymerizable compounds with a molecular weight of 500 or less, A photopolymerization initiator having absorption in at least a portion of the wavelength range of visible light, UV-absorbing compounds, Includes, A method for manufacturing an optical article, wherein, during the above-mentioned light irradiation, an ultraviolet-blocking filter is placed between the light source and the coated layer for at least a portion of the period from the start of the light irradiation. [2] The method for producing an optical article according to [1], wherein the ultraviolet-absorbing compound is a photochromic compound. [3] The method for manufacturing an optical article according to [1] or [2], wherein the wavelength range of the light emitted by the above light source includes a wavelength range of 300 nm to 600 nm. [4] A method for manufacturing an optical article according to any one of [1] to [3], further comprising, during the above-mentioned light irradiation, removing the filter from between the light source and the coated layer after light irradiation with the filter in place, and then performing light irradiation. [5] The polymerizable compound with a molecular weight of 500 or less is (meth)acrylate, the method for producing an optical article according to any one of [1] to [4]. [6] The method for producing an optical article according to any one of [1] to [5], further comprising one or more polymerizable compounds with a molecular weight of 500 or more as the polymerizable composition. [7] The optical article is an eyeglass lens, and the method for manufacturing an optical article according to any one of [1] to [6]. [8] The optical article is a lens for goggles, and the method for manufacturing an optical article according to any one of [1] to [6]. [9] The optical article is the visor portion of a sun visor, and the method for manufacturing the optical article according to any one of [1] to [6].

[10] The optical article is a shield member of a helmet, a method for manufacturing an optical article according to any one of [1] to [6].

[0073] The various embodiments and forms described herein can be combined in any combination of two or more.

[0074] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Industrial applicability]

[0075] This invention is useful in the technical fields of eyeglasses, goggles, sun visors, helmets, and the like.

Claims

1. Applying a polymerizable composition onto a substrate to form a coating layer, The coating layer is cured by irradiating it with light from a light source having an emission wavelength band that includes at least a portion of the ultraviolet wavelength range and at least a portion of the visible light wavelength range. Includes, The polymerizable composition is, One or more polymerizable compounds with a molecular weight of 500 or less, A photopolymerization initiator having absorption in at least a portion of the wavelength range of visible light, UV-absorbing compounds, Includes, The aforementioned ultraviolet-absorbing compound is a photochromic compound, A method for manufacturing an optical article, wherein, during the light irradiation, for at least a portion of the period from the start of the light irradiation, an ultraviolet blocking filter having a maximum transmittance of less than 5% in the ultraviolet wavelength range of 300 nm to 400 nm is placed between the light source and the coated layer, and the light irradiation is performed.

2. The method for manufacturing an optical article according to claim 1, wherein the light source has an emission wavelength band in at least a portion of the wavelength range of 300 nm to 600 nm (provided that at least a portion of the ultraviolet wavelength range and at least a portion of the visible light wavelength range).

3. The method for manufacturing an optical article according to claim 1 or 2, wherein the light source is a metal halide lamp.

4. A method for manufacturing an optical article according to any one of claims 1 to 3, further comprising, during the light irradiation, removing the filter from between the light source and the coated layer after light irradiation with the filter in place, and then performing light irradiation.

5. The method for producing an optical article according to any one of claims 1 to 4, wherein the polymerizable compound with a molecular weight of 500 or less is a (meth)acrylate.

6. The method for producing an optical article according to any one of claims 1 to 5, wherein the polymerizable composition further comprises one or more polymerizable compounds with a molecular weight of 500 or more.

7. The method for manufacturing an optical article according to any one of claims 1 to 6, wherein the optical article is an eyeglass lens.

8. The method for manufacturing an optical article according to any one of claims 1 to 6, wherein the optical article is a lens for goggles.

9. The method for manufacturing an optical article according to any one of claims 1 to 6, wherein the optical article is the visor portion of a sun visor.

10. The method for manufacturing an optical article according to any one of claims 1 to 6, wherein the optical article is a shield member of a helmet.

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